Collins died Tuesday and a funeral is scheduled Sunday. The Atlanta Journal-Constitution reports the cause of death of the 74-year-old Collins wasn't immediately known.

"Mac was a dedicated public servant. He was a hard worker," said Bo Bryant, his former chief of staff. "Like he used to say, he was a graduate of the university of hard knocks."

Collins represented a Macon-based U.S. House district from 1992 to 2004. He stepped down to run for U.S. Senate, losing a Republican primary to Johnny Isakson. He narrowly lost a comeback bid to the U.S. House in 2006.

He started a trucking company driving one beat-up truck, eventually building a successful business. Taking an interest in politics, he was elected to the Butts County Commission in 1976 on his third try, running as a Democrat. Collins switched to the Republican Party sooner than many other rural Southern politicians, though, becoming his county's GOP chairman in 1981. Collins lost two bids for state Senate as a Republican in 1984 and 1986.

"My friends told me if I had run as a Democrat I would have won, and I would have," Collins said.

But the stubborn Collins persisted, winning in 1988 and becoming one of only 11 Republicans in the state Senate.

"He was a pioneering leader of the Republican Party in Georgia, joining at a time that there were no Republicans in power in Georgia," said state Sen. David Shafer, who in 1992 was the executive director of the state GOP.

He jumped to Congress in 1992, two years before fellow Georgian Newt Gingrich led a wave of Republicans to a majority in 1994. In his six terms in the House, Collins served on the Intelligence and tax-writing Ways and Means committees. He quickly became known for his knack for translating Congress' policy moves into language non-Washington types could understand.

Collins eschewed many of Congress' perks. He chose to forgo his lawmaker pension plan, saying that if Social Security was good enough for everybody else, it would also work for him.

He also regularly returned portions of his office operating budget to the Treasury, according to former top aide Mike Joyce, and frequently arrived at the office around 5 a.m. to begin the workday. A few savvy constituents caught onto that fact and would call in early for the chance to speak to the congressman directly.

Republican Gov. Nathan Deal ordered flags at the state Capitol and in Butts County to fly at half-staff Friday through Sunday. Deal appointed Collins to the state Board of Corrections in 2014.